1. Field of the Invention
The present invention relates to a clamp. More specifically, the present invention relates to a surgical breastbone clamp containing a detent mechanism extending between respective opposing clamp halves.
2. Description of the Related Art
The related art involves the performing of medical operations on the open rib cage, such as heart operations. These operations have almost become a routine procedure, one which is often done. In order to open the rib cage, one generally saws the breastbone (sternum) lengthwise, making it possible to spread the ribs apart and work freely in/on the open chest.
After the operation, the chest has to be closed again. In particular, one must create the conditions for the lengthwise separated breastbone to heal once more, which necessarily requires, among other things, a fixation of the two halves of the breastbone in a defined position to each other. A number of techniques are known for this. As a rule, the connecting of the two halves of the sternum is done with surgical thread or by tacking together. However, in a number of problem patients, such as those with a strong chronic cough, there are complications due to the fact that the thread is exposed to strong stress and will break.
More stable alternative techniques, but still not used as standard methods today, are the applying of perforated strips on/in the bone and screwing them together, or the joining and fixing of the halves of the breastbone with a massive clamp.
Among these techniques, one preferred technique uses a generally two-part clamp with two clamp halves, each of which grasps one outer side of a breastbone half. The two halves of the clamp are than moved toward each other until the halves of the breastbone are pressed against each other with the desired pressure and fixed in this position. The advantage with the use of such clamps is that, besides the high-strength connection of the sternum halves which it accomplishes, no further procedures are required for the breastbone, such as making of holes to lead a thread through, applying of perforated strips, or forcing of wire staples into the breastbone with a tacker device.
Clamps which are used for the joining and fixing of the breastbone are known, for example, from DE 8222027, U.S. Pat. No. 6,051,007 or US 2006/0195101 A1. In all of these configurations, the first half of the clamp commonly has an elongated staple-like structure with surface structurization, while the second half of the clamp has a sleeve, which is fitted onto the staple-like structure and is fixed there generally by means of a detent mechanism, provided in or on the sleeve and engaging with the surface structurization, as the two halves of the clamp are moved together into the desired end position.
However, all these clamps have a number of disadvantages in common: it is not possible to achieve a symmetrical and especially a flat bearing surface of the clamp with them. Thus, the primary effect achievable with a clamp, that of a two-dimensional pressure, as opposed to the uni-dimensional pressing of a thread, is thwarted in that the effective bearing surface is ultimately confined to the region of the sleeve. In another common disadvantage, the fixation mechanism only acts locally in a small region of the clamp and is therefore still always exposed to a certain degree of wobbling and tilting and does not achieve the highest conceivable stability. As a third common disadvantage, when tightening the clamp, it is a problem that the relative movement of the halves of the clamp toward each other still occurs only by the movement of one half of the clamp, and so the tightening is necessarily asymmetrical, which can result in a fourth common disadvantage, namely the halves of the breastbone not being fixed in the optimal position relative to each other.
Accordingly, there is a need for an improved surgical clamp that overcomes the drawbacks noted above.